Drawing press



Patented July 2, 1946 DRAWING PRESS Alidor Lefere, Jackson, Mich., assignor to Lefere Forge & Machine Company, Jackson, Mich, a

corporation of Michigan Application April 30, 194-1, Serial No. 391,083

3 Claims.

The present invention relates to drawing presses, and more particularly to a construction for impressing the outside of a drawn blank to shape the same as desired.

The present invention is for the purpose of performing one of the steps in the method of making high explosive shells and like tubular members having one closed end and one open end, disclosed in my copending application Serial No. 391,084, filed April 30, 1941, and now Patent No. 2,338,652, granted Jan. 4,1944. The disclosure of aforesaid application include a step of drawing of forged blanks. Since the forging dies become worn after periods of use, the outside of the closed end of a shell-like member loses its original sharpness According to the present invention, a machine is provided which operates so that as the forged blank is-drawn, the drawing mandrel urges the drawn blank against a resiliently mounted die to impress the outside of the closed end to shape it. Also, the impressing die is provided with numbers or letters by means of which the heat number may be impressed into the end of the drawn blank to identify the same.

An object of the present invention is to employ a drawing mandrel in a drawing machine to, force a blank being drawn thereby against a yieldably mounted impressing die. 1

Another object of the invention is to impress a piece of work by forcing the work against a yieldably mounted die.

Thes and other objects residing in the arrangement, combination and construction of the parts will be apparent from the following specification when taken with the accompanying drawing, in which Fig, 1 is a vertical section of a drawing'press according to the present invention,

Fig, 2 is a partial section of the construction of Fig. 1 taken on the line IIII of Fig. 1,

Fig. 3 is a section on the line III-III of Fig, 1, and,

in, shown particularly in Fig. 2. The support 2 s has connected thereto'a drawing mandrel I The Fig. 4 is a view taken along the line IVIV Open side 1' of the sleeve 6 permits the support 2 and mandrel 8 to swing outwardly, as shown in Fig, 2. The support 2 has connected thereto a rod 9, shown particularly in Fig. 2, on the outer end of which is a counterbalancing weight Ill. The length of the rod 9 and the weight of the counterbalancing weight ID are such that the weight Ioswings the mandrel 8 out to it dotted line position shown in Fig. 2 into a position for receiving work thereon.

Pivoted to the bottom face I5 of the sleeve 6 by a pin I6 is an angulated arm- II, The arm I1 is urged, about the pin I6, as viewed in Fig. 3, in a, counterclockwise direction by a spring I8 having one end thereof connected to the arm I! and the other end thereof connected to a portion of'the machine frame, not shown. The arm I I has pro: jecting therefrom on the opposite side of thepin I6 from the spring I8, a nose portion I9 which is" arranged to hold the mandrel sup-port 2 invertical position. The arm I] is provided'adjacent the nose I9 with a follower surface 20, against which the mandrel support 2 bears on bein swung toward its upright position to cam the arm I! about; its pin IE to permit the return of the mandrel support 2 to its upright position. When the'man-i' drel 8 and its support 2 are in upright position; the tension of the spring I8 is great enough to overcome the tendency of the weight I0 to swing The ram has supported the mandrel 8 and itssupport 2 away from their upright positions,

Associated with the ram I and the drawing mandrel 8 is a press bed 2| from which a platform 23 is supported by legs 22. Arranged on the platform 23 is a drawing die 24 and a trimming die' 25, the trimming die 25 being for the purpose of;

cutting oil the flash from the outside of the blank to be drawn, when the same is formed by forging. Axially slidable in suitable guideways in the platform 23 is a pair of stripper bars 26. Each of the stripper bars 26 is connected to a bar 21, the bars 21 extending along opposite sides of the platform 23. The free ends of the bars 21 are connected by helical springs 28 extending along opposite sides of the platform 23 at right angles to the bars 21: and parallel to the stripper bars 26. The

purpose of the stripper bars 26 is to'yield laterally as work is forced past the drawing die 24 and to move inwardly under the action of the springs 28 when the work has moved pastthem so as to bear against the top edge of the work as th drawing mandrel 8 is returned to its upper 1 position to strip the work from the drawingmandrel 8. g

Arranged immediately beneath the drawing die aaoa, 1 s3 24 is a support'3l having therein an impressing die 32, The impression die 32 has therein removmounted on the bed 2|. v

' In operation a hot blank 36 is disposed on the mandrel 8 when it .is in its dotted outline position disclosed in Fig. 2 Preferably the blank 36 is disposed on the mandrel 8 directly from the forging dies by which it is shaped, while still having its forging heat. The mandrel 3 is disposed in its a dotted outline position by pivoting, the arm l-;l by

means of the handle 31 about. the pi [5, to move the nose l3 awayfrom its position against the mandrel support 2, The counterbalancing weight. It then swings the mandrel 8 forwardly about the ball 3 of the mandrel support 2. When the blank 36 has been placed on the forwardly extending mandrel 8, it. is swung into its upright position camjming the arm l1. about. the pin H3.v by bearing against the follower face 20. of the arm ll. As

'soonas the mandrel supportv 2 is'in its upright v position, the spring l-8' swings the arm I! about its-pin l6 tobring the nose is into position to hold the mandrel support -2 in its upright. position. The machine is then actuated tomove the ram. l

downwardly. It will be understood that as soon as the mandrel 8 islmoved to its uprightposition,

the blank 36 falls downwardly until it rests in the trimming. die 23'. As the mandrel 8 is moved downwardly it. engages with the inside of the. bottom. of the blankI3'6 and forces the blank 33 downwardly while the trimming die 25. trims off the flash 33 on the blank 35, and the drawing die swings the sides of the blank 36 inwardly to provide'a cylindrical blank 33, shown in dotted outnnem Fig. 1. a a

fAsjtherblank 39 is moved past the stripper bars I 2B,;the bars 28 slide laterally against the action of'the springs '23. When the blank 39 has moved completely past the stripper bars 26, they move inwardly under the action of thesprings 23 to the 7 Just before the manposition shown in Fig. l; drelf8freaches its lowermost position itmoves the close'dlend or the blank 39 into engagement with the 'fimpressing die 32. The die 32 is shaped as itis desired t'oT-have the finished shapeofthe. end

of the blank. 39, and. is also provided with the re- 4 movable numbers and letters 33 to impress onthe bottom ofthe blank 39 the number of the heat which i'sibeing r-un, or other desired information. 7

The die '32,, is not intended to be of such configoration as to substantially: alter the form of the outside of theclosed bottom ofthe blank 33, but is merely intended to correctly shape the same to overcome any inaccuracies that ma have arisen due to the wearing .of the forging dies which formed the blank 36. further downwardly forcing the blank 39 against the die 32., the springs 34 yield, It will, of course, be understood that thesprings 34 must oifer sufficientresistance to overcome the resistance to being impressed offered by the blank 3980 that the die 32 will actually make an impression on the outside of the closed end of the blank 33. The resiliency offered by the springs 34 prevents the n l from upsetting as it forces the blank 39 against the die 32. a n

Whenthe outside of. the closed end of. the blank 39 has .beenimpressed by the die 32, the mandrel 8 :is moved upwardly. Since the blank 39 will adhere to the mandrel'8, the stripping bars .26are employed to. overhang the upper edge of the blank 39 to strip it from" them'andrel 8' during the upward movement of the mandrel 8. The blank 39 then falls down into the die 32 from which it is removed'by slightly elevating the blank 39' and then swinging the bottom thereof outwardly and then bodily removing the blank from the press.

The swinging mandrel employed mounted for,

swinging about the ball 3 in the socket 4 is particularly advantageou in the drawing operation, for the reason that the slow moving ram is enabled to travel a much shorter path than would be necessary if the mandrel 8 were not swingable and had to be sufficiently high in order to permit the placing of the blank 36 'thereover at an ele- .vate'd position. By making th mandrel 8 swingable, it is possible to place the blank 36 on the mandrel 8, to swing back the mandrel 8 into its upright position, close to the dies 24 and 25 and to bring the mandrel 8 and blank 36 into operative. relation with the dies 25 and 24 in less time than would be possible if the blank 36 were placed on the mandrel 8 at an elevatedposition.

'While the invention has been described in connection with a step in'the making of high explosive shells disclosed in my aforesaid copending application, it will be understood that the invention is of broader scope and that it may be applied to other types of work. For example, while oneof the most important features of the invention is the combining of the impressing diewith a drawing press, it is contemplated that the idea of impressing work against a resiliently mounted die may be used in association with other types of presses than drawing presses. Also, whil the particular machine employed is designed for drawing blanks having a flash which is trimmed off by the trimming die 25, it will be understood that the trimming of the flash is not an essential movable mandrel for receiving thereon a piece of work open atone end, a drawing die through which the work is forced by said die to draw the As th mandrel 8 moves 'drel and stripping of the work therefrom, said I work, a stripper associated with said mandrel,

operative upon ,ret-urn movement of said mandrel, an impressing die in the path of movement.

of the work moved; by said mandrel, a resilient support for said impressing die, wherebysaid work is moved by said mandrel through said drawing die into engagement with said impressin die to impress the same, the resistance of-' fered by said; support being great enough to overcome the. resistance to being impressed offered by the work, said impressing die being so -arranged that following withdrawing. of the manimpressing die constitutes a support on which the work remains by gravity, and an annular support concentric with, adjacent and beneathsaid-stripper for maintaining the top of the work against,

lateral movement while supported on said die.

2. In a drawing press, an axially vertically movable mandrel for receiving thereon a piece of work open at one end; a drawing me through which the workisforced by said die to draw the work, a press bed, a platform, means resiliently supporting said platform from and above said bed, a stripper associated with said mandrel, ope erative -upon return movement of" said mandrel,

an impressing diemountedon said platform, said impressing die being in the. path of movement of the work moved by said mandreL-wherebysaid work. isxmoved by s'aidmandrel through saiddrawing die into'engagement with said impress- 7 concentric with, adjacent and beneath said stripper for maintaining the top of the work against lateral movement while supported on said die.

3. In a metal drawing press, an axially mov able mandrel for receiving thereon a piece of work open at one end, a drawing die through 6 which work is forced by said mandrel to draw the work, a press bed, a plurality of spaced helical springs supported on end from said bed, a platform supported on the upper ends of said springs, and an impressing die mounted on said platform, said impressing die being in the path of move- "ment of the work moved by said mandrel whereby said work is moved by said mandrel through said drawing die and into engagement with said impressing di to impress the same, the resistance offered by said springs being great enough to overcome the resistance to being impressed offered by the work. 7

ALIDOR. LEFERE. 

